Dental plaque, colonies of harmful bacteria which form on tooth surfaces and restorations, cannot be flushed away by simply rinsing with water. Active brushing of the teeth is required to remove the plaque which adheres to tooth surfaces
It is a well accepted fact that dental plaque, when allowed to accumulate on tooth surfaces, can eventually lead to gingivitis, periodontal disease, caries and calculus. Thus, it is apparent that effective removal of deposits of dental plaque is absolutely essential for oral health. Accordingly, proper oral hygiene practices which may be carried out by an individual on his or her own teeth or by a dentist, would be facilitated by readily available means of identification and location of plaque deposits in the oral cavity.
Since dental plaque is usually transparent and colorless and not easily visible, an individual frequently is not aware of the quantity or the location of dental plaque present in the mouth. Therefore, it is desirable to use plaque-disclosing compositions to identify areas of the mouth where plaque buildup is a problem. The use of disclosing compositions motivates a person in the early removal of dental plaque by showing the presence and quantity of plaque.
Accordingly, dye indicators for dental plaque as a means of measuring tooth cleanliness and to affect proper oral hygiene practices, have been widely explored. A number of agents and techniques have been developed, some of which may be used conveniently and economically at home, whereas others may be used more effectively in a dental office.
Dyes effectively used at a dentist's office include the use of water-insoluble colorants in non-toxic carriers which can only be removed mechanically from the mouth, and fluorescent dyes which require application of a light source to be observable.
A disclosant dye must meet certain criteria in order to be useful as a plaque disclosing agent, particularly for home use. Firstly, the dye must be capable of adequately penetrating the plaque deposit, and stain said plaque so as to be readily visible to the user, without producing an excessively prolonged staining effect. This staining efficacy must be selective so as to identify the areas of plaque-formation on all tooth surfaces and not unduly stain gingival or other oral tissues. This selective staining efficacy must be coupled with easy removability from the mouth by simply washing or rinsing after use, i.e. it should be water-soluble. In addition, the taste must be pleasant and acceptable to the user, and the color must be pleasing. It must be harmless and non-toxic. Further, it should be visible under normal light conditions, not dependent on fluorescence excitation sources.
It is evident that certain previously disclosed plaque-disclosants meet some of the above criteria, but not all. Erythrosine, or FD&C Red No. 3, a currently popularly used water-soluble disclosing dye, has the disadvantage of unpleasant taste, non-discriminatory staining of the gingival tissues, and difficulty of removal from gingival tissues and oral surfaces. Although FD&C Red No. 3 has been widely used, its safety has been called into question and has been prohibited for use in cosmetic products in the United States as of Aug. 29, 1989.
It has been found that FD&C Red No. 40, also known as Allura Red, a water-soluble dye, has the desired attributes of an ideal plaque disclosing agent. This non-toxic dye provides a strong color intensity to the disclosed plaque, which is observable by the naked eye at visible light wavelengths, providing a sharp contrast between the disclosed plaque and surrounding soft and hard oral tissues; is water-soluble so that excess may be substantially rinsed out of the mouth and off of sink surfaces; and is more palatable to the taste than other commonly used disclosing dyes.